A digital network comprises of a group of nodes that are connected to each other through a variety or interfaces. The network can also be logically considered to comprise several layers including, for example, a physical layer, a data link layer, a network layer, and a transport layer. In each of these layers, different agreed upon standards that enable various vendor equipment to communicate may be used. The standards are also known as communications protocols.
In one example of a protocol for the digital network, Asynchronous Transfer Mode (“ATM”) or “cell switching” is a technology designed for transmitting digital information such as voice, video, and data at high speeds through the digital network. In the ATM protocol, the digital information to be transferred is first arranged into equal sized units called cells having fixed lengths. The cells are then transmitted from node to node until they reach a destination node through a pathway (or connection) within the digital network.
The communication path between two nodes is established through a virtual circuit. In a virtual circuit, the path may be established and then removed, and resources along the path may be shared by multiple virtual circuits. When the data cells are sent through network switches that established virtual circuits through an automated call-setup procedure, the communication paths are called Switched Virtual Circuits (“SVCs”). SVCs must be reestablished each time data is to be sent. In contrast, Permanent Virtual Circuits (“PVCs”) and Soft Permanent Virtual Circuits (“SPVCs”) are virtual circuits that are permanently available and are more efficient for connections between nodes that communicate frequently. Thus, a user in a digital network, such as, for example, an ATM network or a Frame Relay network, needs to configure PVCs and SPVCs on a node-by-node basis, which requires proper and timely synchronization of data within the respective nodes.
The digital network is constructed of digital switches coupled together through digital communication links such as, for example, trunks. The trunks carry the cells of information between the digital switches along the connection. The digital switches route the cells from incoming communication links to outgoing communication links and finally to the destination node.
A multiservice digital switch, such as, for example, an ATM multiservice digital switch, includes one or more control modules, such as, for example, one or more controller cards, and several types of service modules, such as, for example multiple line cards. The control modules have a typical 1:1 redundancy and include storage components to store the database configuration belonging to the entire ATM digital switch. Since the storage components are interchangeable and may be replaced independent of one another, the control modules need to ensure that the database configuration information is synchronized and available to all control modules. One solution involves the use of a unique identifier within the ATM digital switch, such as, for example a transaction identifier, for each piece of data residing in a standby storage component and to determine which pieces of data are out of synchronization with the active storage component in the redundant ATM digital switch. However, since the transaction identifier is unique only within the switch, if a storage component native to the switch is replaced with a non-native storage component, the synchronization of data may be affected.